JPH01314803A - Pulverized coal burner - Google Patents

Abstract

PURPOSE:To prevent the wear of rotary blades, to stably perform the function of the blades for a long period of time, and to reduce the production of NOx by covering the faces of the blades at the upstream side of mixture fluid flowing direction which are particularly vigorously worn by the collision of pulverized coal, with ceramics having excellent wear resistance. CONSTITUTION:The end face of a rotary blade 25 at the upstream side is covered, for example, with a first plate 33 made of wear resistant ceramics, such as silicon nitride (Si4N4) or silicon carbide (SiC) or the like. The plate 33 is formed in a U-shape section, and its inner recess 34 is engaged with the protruding stripe 31 of the blade 25. The lower end face of the plate 33 is formed to be oblique, and its inclining angle theta1 is the same as the inclining angle theta2 of the blade 25. The plate 33 is inserted at its lower end into the groove 30 of a cylinder 29 to be completely covered to the root of the blade 25, and secured to the blade 25 by retaining fittings 38 made, for example, or stainless steel.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a pulverized coal burner that conveys a mixed fluid of pulverized coal and a conveying medium such as air into a furnace and burns it. This relates to a swirl vane provided within a supply pipe.

[Conventional technology]

Due to recent changes in the fuel situation, coal-fired boilers that use coal as the main fuel are increasing in boilers for the dollar industry, including large boilers for thermal power plants.

In this coal-burning pore, the coal is pulverized by a pulverizer into, for example, pulverized coal of about 200 mesh passing th of 170% in order to improve the combustion efficiency of the coal fuel.

However, arsenite fuel contains N in fuel components such as C and H, and pulverized coal in particular has a higher N content than gaseous fuel or solid fuel.

Therefore, NOx generated during combustion of pulverized coal is larger than NOx generated during combustion of gaseous fuel and liquid fuel.
For this reason, it is highly desirable to reduce NOx as much as possible.

NOx generated during the combustion of various fuels is thermal (Th
crmal) N Ox and Fuel NO
Thermal NOx is generated when nitrogen in the combustion air is oxidized, and it is highly dependent on flame temperature, and the amount of thermal NOx generated increases as the flame temperature approaches the cavity. . On the other hand, fuel NOx is generated when the N content in the fuel is oxidized, and it is highly dependent on the oxygen concentration in the flame (the more oxygen there is, the more the N content in the fuel becomes fuel NOx). Cheap.

Combustion methods for suppressing NOx generation include:
There are multi-stage combustion methods in which combustion air is divided into multiple stages and injected, and exhaust gas recirculation methods in which combustion exhaust gas with a low oxygen concentration is mixed into the combustion area, but all of these low NOx combustion methods involve combustion through low-oxygen combustion. The purpose is to suppress the generation of thermal NOx by lowering the flame temperature.

However, between thermal NOx and fuel NOx,
It is thermal NOx that can suppress the amount of NOx generated by lowering the combustion temperature, and the amount of fuel NOx generated has little dependence on the combustion temperature.

Therefore, conventional combustion methods aimed at lowering the flame temperature are effective for combustion of gaseous fuels and liquid fuels with low N content, but they usually contain 1 to 2 Wt% nitrogen. The effect on pulverized coal combustion is small.

The combustion mechanism of pulverized coal consists of a thermal decomposition process of pulverized coal in which volatile components are released, a combustion process of the released volatile components, and
It consists of the combustion process of heat-generating solid components (hereinafter referred to as char) after thermal decomposition.

The burning rate of this volatile component is much faster than that of the solid component, and the volatile component burns at the initial stage of combustion. In addition, in the pyrolysis process, the N contained in the pulverized coal I and the pulverized coal are also divided into those that are volatilized and released like other heatable components and those that remain in the char.

Therefore, fuel NOx generated during pulverized coal combustion is
NOx from volatile N minutes and NO from N minutes in char
Of all the fuel NOx, fuel NOx from char is generated only when the char burns, so NOx continues to be generated until the latter half of combustion, and countermeasures against this are an important point.

It is known that volatile N becomes compounds such as NH, HCN, etc. in the initial process of combustion and in the oxygen-deficient combustion region. These nitrogen compounds not only react with oxygen to form NOx, but also serve as reducing agents that decompose the generated NOx into nitrogen.

What is the reduction reaction of NOx by this nitrogen compound?

It progresses in a coexisting system with NOx, and NOx
In a reaction system where NOx coexists, most nitrogen compounds are oxidized to NOx. In addition, the generation of reducing substances progresses more easily as the atmosphere becomes lower in oxygen concentration.

As described above, an effective method for reducing NOx during pulverized coal combustion is a combustion method in which a volatile nitrogen compound having a reducing property and NOx coexist, and the nitrogen compound reduces NOx to nitrogen.

In other words, a combustion method that eliminates the generated NOx and the NOx precursor by using a reducing nitrogen arsenate such as NHa, which is a NOx precursor, is effective for reducing NOx. It is.

FIG. 12 is a sectional view of a conventional pulverized coal burner for burning pulverized coal.

The pulverized coal burner l has a mixed fluid 26 of pulverized coal and primary air.
, or a mixed fluid 26 of pulverized coal and combustion exhaust gas, or a mixed fluid 26 of pulverized coal, primary air, and combustion exhaust gas in the furnace 2.
It is mainly composed of a pulverized coal supply pipe 3 that injects the coal into the tank, and an elbow 4 that extends horizontally from below. A splash plate 5 for changing the flow direction of the mixed fluid is disposed in the elbow 4, and a pulverized coal supply passage 6 is formed inside the elbow 4 and the supply pipe 3.

On the outer periphery of the pulverized coal supply pipe 3, a partition plate 10 and a sleeve 1 are arranged inside the wind box 7 to supply combustion air from the wind box 7 to the burner boat 9 side of the furnace wall 8.
1 into a secondary air passage 12 and a tertiary air passage 1
3 is formed.

The secondary air passage 12 and the tertiary air passage 13 include a secondary air register 14 and a tertiary air register 15, respectively.
are arranged so that the combustion air flow rates in the secondary air passage 12 and the tertiary air passage 13 are controlled.

On the other hand, a flame stabilizer 18 is provided at the tip of the pulverized coal burner l, and this flame stabilizer 18 consists of a serrated flame stabilizer plate 16 (see FIG. 13) that protrudes inward in the radial direction of the supply pipe 3. and furnace 2
It is composed of a flame-holding ring 17 that expands toward the flame-holding ring 17.

A contracted flow section 22 having a small diameter is formed near the inlet side of the pulverized coal supply pipe 3 . Further, a starting burner 19 is inserted along the axial direction approximately at the center of the pulverized coal supply pipe 3, and a support member 21 is inserted on the downstream side of the contraction section 22.
The tip side of the starting burner 19 is supported and fixed. An annular body 23 through which the starting burner 19 passes is integrally provided at the upper end of the support body 21, and a step is formed between this annular body 23 and the outer peripheral surface of the starting burner 19 on the upstream side thereof. Since this level difference adversely affects the flow state of the mixed fluid, a rod protector 24 having an inclined outer circumferential surface whose outer diameter gradually increases is arranged adjacent to each upstream side of the annular body 23. There is.

Further, a plurality of swirling vanes 25 are attached to the outer circumferential surface of the tip of the starting burner 19, and apply a swirling force to the mixed fluid 26 conveyed through the supply pipe 3.

In the pulverized coal burner having such a configuration, the mixed fluid 26 of pulverized coal is injected into the furnace 2 from inside the flame stabilizer 18, but a vortex 20 is formed inside the flame stabilizer plate 16 as shown in FIG. The pulverized coal is drawn in by this 2° swirl, and air is drawn in from the outside to reliably form an ignition flame.

Further, the mixed fluid 26 is swirled by the swirling vanes 25, so that a reduction zone I with a high concentration of pulverized coal is formed near the outlet of the pulverized coal burner 1.

In this reduction zone I, pulverized coal is decomposed by combustion into volatile nitrogen compounds (Volatile N) and nitrogen compounds in char (Char N) as shown in the following formula.

Total Fuel N-+Volatile
N CharN... (1) This Volatile N is a reducing intermediate product, ・N Hz, ・CN, etc. radicals and CO
Contains reducing intermediates such as

A small amount of NOx is generated locally within this reduction zone I, but this is converted into reducing radicals by carbon f arsenic radicals ((fl, for example, Cl-1) in the pulverized coal, as shown in equation (2). will be converted.

80・CH→・NH+GO・・・・・・(2) Next, around the reduction area 1, secondary air is supplied from the secondary air passageway 2.
In other words, Volatile N from the reduction zone! and nitrogen (N2) in the air are oxidized and fuel is formed as shown in the first equations (3) and (4). NO and herbal NO
generate.

2 Volatile N + 02→2NO(fu
el No)・・・・・・(3) N2 +02 →2NO(thermal No)・
...(4) Furthermore, in the denitrification zone ■ on the downstream side, the No generated in the oxidation zone ■ and the reduction zone! The reducing intermediate product (.NX) in the nitrogen reacts to generate N2 as shown in the following equation (5), and self-denitrification is performed. Here, X in NX represents Hz, C, etc.

N O・To・NX → N, l + X
O... (5) Afterstream of the denitrification zone ■ (in the complete combustion zone ■ formed on the right side when facing the drawing in Fig. 14,
The tertiary air from the tertiary air passage 13 is supplied to the downstream side of the denitrification zone (2), where the char containing the aforementioned charN,
Unburned matter is completely combusted.

[Problem to be solved by the invention]

In this conventional pulverized coal burner, the support 21.

The rod protector 24, swirl vane 25, etc. are made of metal. On the other hand, the pulverized coal flow accelerated by the contraction section 22 has a rapid flow velocity. Therefore,*
A support 21 on which the powdered coal collides at a predetermined angle. The upstream surfaces of the rod protector 24 and the swirling vanes 25 are extremely worn, which not only necessitates replacement of parts within a short period of time, but also reduces the self-denitrification function as described above.

In particular, the flow velocity distribution of pulverized coal in the pulverized coal supply pipe 3 is
As shown in FIG. 5, the flow velocity is highest approximately at the center of the supply pipe 3, and the flow velocity gradually decreases as it approaches the pipe wall. However, in the case of this pulverized coal burner, as shown in FIG. 12, the mixed fluid 26 containing pulverized coal is supplied from below, changed direction and is injected horizontally, so that due to the centrifugal force applied to the pulverized coal, In the pulverized coal supply pipe 3, the flow velocity is generally higher above the center than below the center, and the flow velocity distribution is not vertically symmetrical.

For this reason, the most abrasive parts are near the root of the swirl vane 25, followed by the center of the support leg 27 and the center of the outer peripheral surface of the rod protector 24.

The purpose of the present invention is to eliminate such drawbacks of the prior art,
It is an object of the present invention to provide a pulverized coal burner that has a long service life and always provides a stable denitrification function.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention provides a heating fluid containing pulverized coal and a conveying medium such as secondary air or combustion exhaust gas at a predetermined position in a pulverized coal supply pipe that conveys and injects it to the furnace side. In a pulverized coal burner provided with a plurality of swirling vanes for imparting swirling force to the conveyed mixed fluid and injecting it from a supply pipe.

The upstream side of the swirl vane in the mixed fluid flow direction.

For example, silicon nitride (S I jN4) and carbon
It is characterized by being covered with a ceramic body made of StC) or the like.

[Effect]

By covering the upstream side of the swirler in the direction of mixed fluid flow, which is particularly prone to wear due to collisions with pulverized coal, with a highly wear-resistant ceramic body, we are able to prevent wear and extend the functionality of the swirler. It can perform stably over a period of time and contribute to reducing NOx.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a pulverized coal burner according to an embodiment of the present invention;
Figure 2 is a partially cross-sectional front view of the swirling vane attached to the pulverized coal burner, and Figure 3 is a partially cross-sectional view showing the swirling vane with the first plate and holding fitting attached. Figure 4 is a view taken from the X arrow in Figure 3.
Figure 5 is a front view of the first plate, Figure 6 is Figure 5 Y-Y
7 is a top view of the presser fitting, FIG. 8 is a sectional view of the presser fitting, FIG. 9 is a partially sectional front view of the rod protector and support, and FIG. 10 is a top view of the presser fitting. 9 is a left side view, and FIG. 11 is an exploded front view for explaining the state in which the second plate and fixing fittings are attached to the support body.

As shown in FIG. 1, the main structure of the entire pulverized coal burner 1 is the same as that of the conventional one shown in FIG. A starting burner (oil burner) 19 is inserted into the center of the pulverized coal supply pipe 3 along its axial direction. Six swirling vanes 25 are attached to the tip of the starting burner 19 in the circumferential direction, and a support 21 is provided between the swirling vanes 25 and the contraction section 22. A starting burner 19 is supported and fixed to the pulverized coal supply pipe 3.

As shown in FIG. 2, the swirling vane body 28 is composed of a cylindrical body 29 and six swirling vanes 25 that are erected slightly obliquely in the circumferential direction of the cylindrical body 29. is integrally formed from casting. An annular groove 30 is formed at approximately the center of the outer circumferential surface of the cylinder 29, and its m3
A swirling vane 25 stands obliquely adjacent to the trailing edge of the shaft 2. A protrusion 31 is formed on the upstream end face of each swirling vane 25 in the mixed fluid flow direction over almost its entire length, and the root of the protrusion 31 faces the groove 30 .

Further, a screw hole 32 for attachment is provided on the upper surface of each swirling blade 25.

The upstream end surface of the swirl vane 25 is made of silicon nitride (S), for example.
It is covered by a first plate 33 made of a wear-resistant ceramic such as silicon carbide (SIG) or silicon carbide (SIG). The first plate 33 has a U-shaped cross section as shown in FIG.
It is designed to fit with the protrusion 31 of.

The lower end surface 35 of the first plate 33 is an inclined surface,
This angle of inclination θl is the same as the angle of inclination 02 of the swirl vane 25 (see FIG. 3). As shown in Figure 5,
At the upper end of the swirling blade 33, there is an engagement stepped portion 3 which is lowered one step further.
6 is provided, and an engagement #37 on this engagement step portion 36 is formed.

As shown in FIG. 3, the lower end of the first plate 33 is inserted into #30 of the cylindrical body 29 to completely cover the root of the swirling blade 25.

This first plate 33 is fixed to the swirl vane 25 by a presser metal fitting 38 made of stainless steel, for example.

That is, an engaging claw 39 is provided at one end of the presser metal fitting 38 and projects downward.

Two screw insertion holes 40 are formed on the downstream side of the engagement claw 39. For example, as shown in FIG. 3, after covering the end surface of the swirling vane 25 with the first plate 33, the upper surface of the swirling vane 25 is moved so that the retaining metal fitting 38 is inserted into the engaging groove 37 with its engaging claw 39. By placing the first plate on the cylindrical body 2 and screwing the holding fitting 38 to the swirling vane 25 with a retaining screw 41 made of stainless steel, the first plate is connected to the holding fitting 38 and the cylinder body 2.
It can be held between 9 and 9.

In this state, when screwing is completed, presser metal fitting 38
In addition, the countersunk screw 41 is attached to the first plate 3 in consideration of wear.
It is designed so that it does not protrude from the top surface of 3. In addition,
As shown in FIG. 6, at the outer corner of the first plate 33,
The roundness 42 is provided to smooth the flow of the mixed fluid 26 containing pulverized coal and to avoid wear. This roundness 42
A taper may be used instead.

Next, the structure of the support body 21 will be explained using FIGS. 9 to 11. The support body 21 is composed of a leg portion 27 and an annular body 23 provided at the upper end of the leg portion 27, and the annular body 23 of the leg portion 27 is integrally formed, for example, by casting. As shown in FIG. 1, the lower end of this leg portion 27 is attached to the inner surface of the pulverized coal supply pipe 3 via a base plate 43, while the starting burner 1 is attached to the annular body 23.
9 is passing through.

As mentioned above, since the annular body 23 is made of cast metal,
This cannot be directly welded to the starting burner 19 (for example, made of stainless steel), so an engagement ring 44 made of carbon steel or the like is integrally engaged with the downstream side of the annular body 23 by a reverse taper. By fillet welding 45 the engagement ring 44 and starting burner 19, the annular body 23
can be indirectly connected to the starting burner 19. With such a connection structure, the IM-like body 23 connects to the starting burner 1.
If a force is applied to move the ring 9 to the right in the drawing, it will be blocked by the weld 45, and if a force to move it to the left is applied, the engagement between the annular body 23 and the engagement ring 44 will be prevented. It is blocked by the reverse taper of the joint.

As shown in FIG. 11, a protrusion 46 is formed on the upstream end face of the mixed fluid flow direction of the one leg portion 27 over almost its entire length, and a protrusion 46 is formed on the lower end face of the annular body 23 near the protrusion 46. An engagement groove 47 is provided. The second plate 48 that covers the upstream end surface of the leg portion 27 is made of silicon nitride (Si), for example.
It is made of wear-resistant ceramics such as carbon (iNa) and carbon (SiC). Its cross-sectional shape is U-shaped so as to engage with the protrusion 46, and a protrusion 49 is formed at the upper end of the second plate 48 to be inserted into the engagement a47.

As shown in FIG. 9 and FIG.
9 is inserted into the engagement groove 47 and the upstream end surface of the leg portion 27 is covered with the second plate 48 .
8 is fixed with a fixing fitting 50.

That is, an engaging pawl 51 is provided at one end of the fixing metal fitting 50 to project upward, and two screw holes 52 are formed on the downstream side of the engaging pawl 51. After attaching the second plate 48 to the leg portion 27, the engaging claw 5 of the fixing metal fitting 50
1 on the lower end of the second plate 48, and
By fixing the second plate 48 to the lower end of the leg portion 27 with the screw 53, the second plate 48 can be held between the annular body 23 and the fixture 50.

In addition, as shown in FIGS. 9 and 10.

Although the engaging claws 51 of the fixture 50 protrude from the second plate 48, as is clear from the flow velocity distribution of pulverized coal shown in FIG. It has been confirmed through experiments that the engagement claw 51 is exposed and hardly wears out due to the slowness of the engagement.

In this embodiment, when the mixed fluid 26 is supplied from below and turned horizontally to be ejected as shown in FIG. Established. However, when the mixed fluid 26 is supplied from above and ejected horizontally, the legs 27 are connected to the starting burner 19.
The starting burner 19 may be suspended by the support 21.

As shown in FIG. 9, a rod protector 24 is fitted on the upstream side of the annular body 23.
4 is also made of a wear-resistant ceramic such as silicon nitride (S l j N4) or silicon carbide (SiG), and its outer diameter gradually increases to protect the annular body 23 so that it forms an inclined surface. have.

By holding the first plate 33 between the presser fitting 38 and the cylindrical body 29 as in the above embodiment, the first plate 3
3 can be easily and reliably fixed. In addition, at that time, attach the presser metal fitting 38 to the rotating blade 2 with a screw 41 or the like.
5, the first play 1-
33 and the presser fitting 38 can be easily replaced.

Furthermore, as in the above embodiment, if a recess such as a groove 30 is provided in the cylinder 29 and the lower end of the first plate 33 is inserted into the recess to cover the end surface of the swirl blade 25, the root of the swirl blade 25 can be can be reliably protected from.

Moreover, if the upstream end surface of the leg part 27 of the support body 21 is also covered with the second plate 48 made of ceramics as in the embodiment described above, wear of the leg part 27 can also be prevented. At this time, if the structure is such that the second plate 48 is held between the fixture 50 and the annular body 23.

Fixing of the second plate 48 is easy and reliable.

Furthermore, if a recess such as an engagement groove 47 is formed in the annular body 23 and one end of the second plate 48 is inserted into this recess to cover the end surface of the leg 27, the annular body 23 of the first leg 27 can be formed. can be reliably protected from the base of the Also, the second
If the plate 48 and the fixture 50 are removably fixed using screws 53 or the like, the second plate 4
8 and the fixing fittings 50 are easy to replace.

Furthermore, as in the above embodiment, if the rod protector 24 is also made of ceramics, the rod protector 24
It can also prevent wear on the peripheral surface.

Next, the first plate 33. A phrase describing the materials of ceramics used for the second pullet 48, rod protector 24, etc. Ceramics include aluminum oxide, carbon dioxide, etc.
i4, magnesium oxide, acid C-hyzirconium.

Subinne/L/ (M g O-A Q z Oj)
, Mura(t(3A Q 20 ,' 2 S t
oz), silicon carbide, boron carbide, boron nitride,
Aluminum nitride, silicon nitride, titanium nitride, etc. can be used, and among them, silicon nitride and silicon carbide can be used.

When using the above-mentioned first plate 3:3, second plate 48, rod protector 24, etc., the following conditions must be considered.

(1) Hardness Compared to conventional burner wear-resistant materials (wear-resistant cast steel, etc.),
Must have sufficient hardness.

(2) Bending strength Tightening at each part must have sufficient resistance against external forces such as force.

(3) High-temperature strength The area near the tip of the burner becomes quite high due to radiant heat from the fire path, but the burner must have a certain level of strength even at such high temperatures.

(4) Thermal Shock Resistance In the process of transitioning from cavity-like tfIA (by radiation from the furnace) to cooling-like 1rIA (by pulverized coal flow containing secondary air, etc.) at the time of ignition, as when the burner body is stationary, Must have sufficient strength to withstand heat WI blows.

(5) Heat resistance Capable of resisting the strong radiant heat from the furnace.

Next, various properties of various materials are shown.

(Silicon nitride) ■, Vickers hardness [Load ffi 500 g Same as below J1780 (kg/mm'') 2, Bending strength 6000 Ekg/cm' 13
, high temperature bending strength [below 1000°C, same below] 5500
[kg/cm') 4. Thermal shock resistance [After heating the test piece to 400°C, drop it into water (
20° C.) and subjected to thermal shock, the bending strength was measured. Same as below 3 6000 [kg/Cm"J5, Maximum operating temperature 1200℃ (Silicon carbide #) 1, Vickers hardness 2000 (kg/mm')
2. Bending strength 5500 [kg/cm' 1
3 HIQ warm bending strength 5500 (kg/cm'
)4, Thermal shock resistance 5500 [kg/cm']
5. Maximum operating temperature 1200℃ (alumina) 1. Vickers hardness 1670 (kg/mm')
2. Bending strength 3180 [kg/cm' 13
, High temperature strength 2200°C 4. Thermal shock resistance Unmeasurable due to destruction 5. Maximum operating temperature 1590°C (Heat-resistant cast steel) 1. Vickers hardness 600 [kg/mm']5
, Maximum operating temperature: 790° C. As is clear from these results, silicon nitride and silicon carbide are especially suitable materials that fully satisfy the conditions 1 to 5 above.

In addition, in the above embodiment, an example was shown in which the starting burner was installed inside the pulverized coal supply pipe, but the present invention is not limited to this. For example, a support member may be provided within the pulverized coal supply pipe, and the swirl vane may be directly fixed to it. It can also be a structure.

【Effect of the invention〕

According to the present invention, since the upstream side of the swirl vane, which is most susceptible to wear by the pulverized coal flow, is protected by a ceramic body with excellent wear resistance, there is no wear of the swirl vane, and therefore the service life of the pulverized coal burner is reduced. It has the advantage of being able to extend the length of the swirling vane and reliably exhibit the function of the swirling vane for a long period of time, thereby contributing to lower NOx.

[Brief explanation of the drawing]

1 to 11 are for explaining a pulverized coal burner according to an embodiment of the present invention, FIG. 1 is a cross-sectional view of the pulverized coal burner, and FIG. 2 is a rotating shaft attached to the pulverized coal burner. A front view with a part of the blade body in cross section, FIG. 3 is a front view with a part in cross section showing the state in which the first plate and the presser fitting are attached to the rotating blade body, and FIG. 4 is a front view with a part in cross section 5 is a front view of the first plate, FIG. 6 is a sectional view taken along the line Y-Y in FIG. 5, and FIG. 7 is a top view of the presser fitting.
FIG. 8 is a sectional view of the presser fitting, and FIG. 9 is a partially sectional front view of the protector and support body. Figure 10 is a left side view of Figure 9, and Figure 11 is a second view of the support.
FIG. 3 is an exploded front view for explaining a state in which the plate and fixing fittings are attached. Fig. 12 is a sectional view of a conventional pulverized coal burner, Fig. 13 is a side view of the pulverized coal burner as seen from the furnace side, Fig. 14 is an explanatory diagram for explaining the function of the pulverized coal burner, and Fig. 15
The figure is a characteristic diagram showing the flow velocity distribution state of pulverized coal in the pulverized coal supply pipe. 1...pulverized coal burner, 2...furnace,
3... Pulverized coal supply pipe, 6... Pulverized coal supply passage, 19... Starting burner, 21.
... Support body, 22 ... Contraction part, 2
3... Annular body. 24...Rod protector, 25...Swirl vane, 26...Mixed fluid, 27...Support leg, 28...
...Swivel blade body, 29...Cylinder body, 30
······groove. 31... Projection, 32... Screw hole, 33... First plate, 37...
Engagement groove, 39...Engagement claw, 41...
...Countersunk screw, 46...Protrusion, 47
......Engagement groove, 48...Second plate,
49...Protrusion. 50... Fixing metal fittings, 51... Engaging claws, 52... Screw holes, 53...
··screw. Fig. 1 Fig. 5 1Q Fig. 11 F3 Fig. 13 Fig. 14

Claims (1)

[Claims] (1) Transporting a mixed fluid of pulverized coal and a transport medium into a furnace;
In a pulverized coal burner, a plurality of swirling vanes are provided at predetermined positions in a pulverized coal supply pipe for applying a swirling force to the conveyed mixed fluid and ejecting it from the pulverized coal supply pipe. A pulverized coal burner characterized in that a surface on the upstream side in the flow direction of the mixed fluid is covered with a ceramic body. (2) In claim (1), the base portions of the plurality of swirl vanes are integrally connected by a cylinder, and the ceramic body is connected between the presser member attached to the upper end of the swirl vane and the cylinder. A pulverized coal burner characterized by being sandwiched between. (3) The pulverized coal burner according to claim (2), wherein a recess is formed on the upstream side of the base of the swirling blade of the cylindrical body, and one end of the ceramic body is inserted into the recess. (4) The pulverized coal burner according to claim (2), wherein the pressing member is detachable from the swirling blade. (5) The pulverized coal burner according to claim (2), wherein the upper surface of the pressing member does not protrude from the upper surface of the ceramic body. (6) In claim (2), a protrusion extending in the upstream direction of the blade is provided on the upstream end face of the swirling vane, and a recess that engages with the protrusion is formed in the ceramic body, A pulverized coal burner characterized in that an engagement recess is provided at the upper end of the ceramic body, and an engagement pawl that is inserted into the engagement recess is formed on the pressing member. (7) In claim (1), the swirling vane is supported in the pulverized coal supply pipe by a support member, and the surface of the support member on the upstream side in the flow direction of the mixed fluid is provided with a protector made of ceramics. A pulverized coal burner characterized by being covered. (8) In claim (7), the swirling vane is supported by a rod, the support body consists of an annular body and legs integrally connected to the annular body, and the rod penetrates the annular body. An annular ceramic rod protector is disposed on the upstream side of the annular body in the mixed fluid flow direction, and a surface of the leg portion on the upstream side in the mixed fluid flow direction is covered with a ceramic plate. Characteristic pulverized coal burner. (9) The pulverized coal burner according to claim (8), wherein a recess is formed on the upstream side of the base of the leg of the annular body, and one end of the plate is inserted into the recess. (10) The pulverized coal burner according to claim (8), characterized in that a fixing member is attached to an end of the leg so that the plate is held between the fixing member and the annular body. (11) The pulverized coal burner according to claim (10), wherein the fixing member is detachable from the leg. (12) In claim (10), a protrusion extending in the upstream direction of the leg is provided on the upstream end surface of the leg, a recess that engages with the protrusion is formed in the plate, and the plate is provided with a recess that engages with the protrusion. A pulverized coal burner characterized in that one end of the fixing member is provided with an engaging pawl that engages with an end of the plate. (13) Claim (1) statement, claim (7) statement, or claim (8)
The pulverized coal burner described herein is characterized in that the ceramic is silicon nitride or silicon carbide.